1. Field of the Invention
This invention relates to a plate stocker adaptable to temporarily stock metal or non-metal plate members, such as rectangular substrates for printed circuit boards, hereinafter referred to simply as--plates--, having a regular or irregular size, length, or width. Such a plate stocker is also adaptable to be situated between two adjacent processes in a plate making or working line in order to receive the plates, one by one, from the preceding process and feed the plates, one by one, to the subsequent process.
2. Description of the Related Art
In a plate making or working line, such as for printed circuit substrates, there are generally several processes, each provided with a working machine, inspecting or measuring installation, and so forth, and these processes constitute a working line through which the plates are transferred. However, the plate feeding speed is not constant in the respective processes, due to differences in the size, length, width, or thickness of the plates, and differences in the working capacity of the respective processes. Therefore, it is usually necessary to insert a stocker between adjacent preceding and subsequent processes.
A plate stocker having, for example, a belt or chain conveyor means for receiving the plates from the preceding process and discharging the plates to the subsequent process is widely known in the prior art. However, such belt or chain conveyor means cannot usually conduct the plate receiving and discharging operations independently of each other. Therefore, if the plate feeding speed of the preceding process is different from that of the subsequent process, the above-mentioned type plate stocker usually cannot smoothly receive the plates at a speed in accordance with the preceding process and also usually cannot smoothly discharge the plates at a speed in accordance with the subsequent process.